esquilax

In the Simpsons episode 2F15 "Lisa's Wedding," the town of Springfield holds a renaissance fair. Police Chief Clancy Wiggum runs "Friar Wiggum's Fantastical Beastorium"–a weird bestiary of amazing mythical creatures. The posters advertise such incredible monsters as the griffin, unicorn, manticore and other such delights, but the chief introduces us to only two: the two-headed dog that was born with only one head and the esquilax, described by Wiggum as "a horse with the head of a rabbit and ... the body of a rabbit."

The esquilax, while seemingly indistinguishable from a regular rabbit, is a mystical beast–following an esquilax into the woods could lead a person to a creepy fortune teller who may foresee the future.

There are no hard-and-fast rules for recognizing an esquilax. The clever beast appears to every test to be a regular old, run-of-the-mill bunny rabbit. It is possible that esquilaxes (esquilaces?) may be spotted by their cartoony appearance–looking suspiciously like Matt Groening's Life in Hell bunnies, with that characteristic overbite. Still, it may be possible that the esquilax can look just like 3-D, non-cartoon rabbits when they are in our non-Simpson world.

If you spot an odd-looking rabbit, you may have found the legendary esquilax. Follow that esquilax! You never know, adventure and prophecy may be just around the corner ...

"Why do you always draw bunnies?"—Will Groening, Matt Groening's son.
"Can't you draw nothing else but bunnies?"—Will again
"Do you love bunnies?"—Will again
"Do you have a job?"—Will again
"Don't yell at dad. He yikes to draw bunnies."—Abe Groening, Matt's other son.

Reference:
The Simpsons Archive, a treasure-trove of all things Simpson: http://www.snpp.com/episodes/2F15.html
Groening, Matt, "the Huge Book of Hell" (Penguin Books, New York, 1997).